This invention relates to an apparatus for cutting lumber to random or specified clear lengths and in particular to such an apparatus having at least one movable sliding saw for removing sections containing defects from the lumber with the minimum amount of waste.
When clear lumber having no defects or flaws is desired, larger pieces of lumber must be cut transversely to remove the sections containing the defects. Cutting apparatus having two saws for removal of the defects simultaneously are known in the prior art. For example, such an apparatus is shown in U.S. Pat. No. 3,811,353.
However, the prior art lumber cutting apparatus have saws which are spaced apart a fixed distance calculated to be coextensive with most defects. If the saw spacing is set to accommodate the largest defect length, which it must be if the apparatus is not always to be shut down for respacing of the saws, when a defect covering a shorter length is removed necessarily a portion of clear lumber is removed also. Thus a portion of clear lumber is lost with most, if not all, of the cuts. This is wasteful and raises the cost of the clear lumber product.
It is the general purpose of the present invention to provide an apparatus for cutting lumber to random or specified clear lengths having at least one fixed saw and at least one longitudinally movable sliding saw for removing defects from the piece of lumber with the minimum removal of clear lumber or for cutting it to a specified length.
It is a further object of the present invention to provide an apparatus for cutting lumber to random or specified clear lengths having infeed and outfeed means adapted for transporting the piece of lumber and for clamping it during sawing at points adjacent the respective cuts.
It is a further object of the present invention to provide an apparatus for cutting lumber to random or specified clear lengths having outfeed means translatable with the sliding saw in order to provide support for the lumber and clamp it during sawing immediately adjacent to the sliding saw, and which is configured to transport the piece of lumber at the same linear speed as the infeed means at all times allowing the sliding saw to be moved simultaneously with translation of the piece of lumber.
It is a further object of the present invention to provide an apparatus for cutting lumber to random or specified clear lengths wherein the lumber is transported in a positive manner for precision indexing longitudinally in the apparatus giving accurate location of the cuts.
It is a further object of the present invention to provide an apparatus for cutting lumber to random or specified clear lengths wherein only one of a pair of saws need be actuated for end cutting the lumber or making intermediate cuts to a specified length when no defect is to be removed.
It is a further object of the present invention to provide an apparatus for cutting lumber to random or specified clear lengths wherein the defects and end trims are removed from the apparatus immediately upon cutting.